Faculty Bibliography

BACKGROUND:Weight management strategies before total hip arthroplasty (THA) include bariatric surgery and Glucagon-like peptide-1 receptor agonists, including semaglutide. Previous studies have reported higher THA implant failure in patients who had prior bariatric surgery. This study aimed to evaluate semaglutide as a weight management alternative for patients undergoing THA and any effects on perioperative outcomes. METHODS:A retrospective review of primary, elective THAs performed between 2012 and 2024 was conducted at a single, urban, academic center. The study identified 224 patients who had a history of bariatric surgery, 202 patients who had perioperative semaglutide use, and a control group of 2,991 patients who had a body mass index (BMI) > 35. Demographic variables and clinical outcomes were compared between cohorts. RESULTS:The bariatric patients were younger (57 versus 61, P = 0.012) and more often women (65.6 versus 57.4 versus 55.4%, P < 0.001) than semaglutide and control patients. Preoperative hemoglobin A1c was lowest in semaglutide patients (6.2 versus 5.7 versus 5.8%, P < 0.001). The changes in BMI varied across groups one year before and after THA (P < 0.001). The bariatric and semaglutide groups decreased their BMI by 1.4 and 0.8, respectively, and control patients increased by 0.4. Implant survivorship was 95.5% at 10 years. There was no correlation found between any cohort and 90-day emergency department visits, readmissions, and all-time revision. Higher American Society of Anesthesiologists class and Charlson Comorbidity Index ≥ 5 conferred increased complications. CONCLUSIONS:Semaglutide appears to be a safe alternative to bariatric surgery for weight management before THA, with similar implant survival and postoperative complication rates. Further studies are warranted to understand outcomes for THA patients who use semaglutide.

BACKGROUND:The impact of postoperative antithrombotic therapy (ATT) on complications such as periprosthetic joint infection (PJI) after total knee and hip arthroplasty (TKA and THA, respectively) remains understudied. We aimed to evaluate temporal trends in ATT use and the association between ATT type and PJI following primary TKA and THA. METHODS:We retrospectively reviewed 20,376 TKA and 16,076 THA patients receiving postoperative ATT between 2013 and 2025. Trends in ATT use were analyzed for all patients, but PJI incidence (2018 International Consensus Meeting definition) was assessed only in patients who had a minimum 90-day follow-up (14,663 TKA; 11,445 THA). Of these, 0.8% and 1.3% developed a PJI, respectively. Multivariate logistic regressions adjusted for age, sex, body mass index, smoking, and the Charlson Comorbidity Index were applied to assess the association between ATT and PJI. RESULTS:From 2013 to 2025, aspirin monotherapy increased to account for the majority of prophylaxis (TKA: 2.0 to 59.4%; THA: 3.1 to 82.2%). In contrast, the use of low-molecular-weight heparin (LMWH) declined (TKA: 87.6 to 0.8%; THA: 86.7 to 2.3%), as did warfarin (TKA: 4.1 to 0.3%; THA: 3.4 to 0.9%) and rivaroxaban (TKA: 6.8 to 4.2%; THA: 8.9 to 2.8%). During the same period, apixaban use increased (TKA: 0 to 10.0%; THA: 0 to 12.7%). Aspirin monotherapy was associated with lower odds of PJI compared to non-aspirin regimens (adjusted odds ratio [OR] 0.60, 95% confidence interval [CI] 0.45 to 0.81, P = 0.001). Conversely, warfarin (OR 8.01, 95% CI 3.41 to 18.88, P < 0.001) and LMWH (OR 1.89, 95% CI 1.35 to 2.64, P < 0.001) were independently associated with increased PJI risk in THA. CONCLUSION/CONCLUSIONS:Aspirin has become the dominant postoperative ATT agent. In THA, aspirin is associated with a significantly decreased risk of PJI compared to potent anticoagulants like warfarin and LMWH, while no such association was found in the TKA cohort. Surgeons should prioritize aspirin to minimize postoperative infection risk.

INTRODUCTION/BACKGROUND:While the learning curve for direct anterior approach (DAA) total hip arthroplasty (THA) is steep, no classification exists to predict technically challenging cases. We propose and validate a new Davidovitch direct anterior (DDA) classification system for predicting DAA THA case complexity. METHODS:We retrospectively reviewed primary DAA THAs by two fellowship-trained surgeons (October 2019 to June 2025). Exclusions included fracture, contralateral hardware, incomplete pelvis radiographs, or less than one year of follow-up. Cases were grouped into learning curve, proficient, and expert phases. Classification was based on preoperative antero-posterior (AP) pelvis radiographs. Operative time served as a proxy for case difficulty. Univariate and multivariate regressions assessed the effects of classification, surgeon experience, fixation method, and body mass index (BMI). RESULTS:Multivariate analyses of 283 cases, including DDA classification, surgeon experience, fixation method, and BMI, demonstrated that operative times were significantly longer for DDA 4 versus DDA 1 cases (P = 0.011). Operative time decreased across learning curve, proficient, and expert phases (P < 0.001). Higher BMI (P < 0.001) and cemented fixation (P = 0.004) independently increased operative time. There were 13 overall complications and two revision THAs within 90 days. CONCLUSION/CONCLUSIONS:This novel radiographic classification system predicted case difficulty in DAA THA, as DDA 4 cases took longer than DDA 1 cases, particularly during the learning curve. Beyond the learning curve, the impact of DDA classification on operative time diminished. This classification system has the potential to serve as a valuable preoperative tool for operative planning and workday efficiency, particularly for early-career surgeons on their learning curve.

BACKGROUND:Prolonged retention of antibiotic-loaded articulating spacers after the first stage of a two-stage revision for periprosthetic joint infection (PJI) can occur because of patient preference, surgeon preference, or medical reasons that prevent the planned second stage. Little is known about the frequency of persistent infections, mechanical complications, and functional results in patients with retained spacers. QUESTIONS/PURPOSES/OBJECTIVE:At a minimum follow-up of 2 years after spacer placement, among patients who do not undergo the second stage revision (replacement of the spacer with a definitive prosthesis of the hip or knee): (1) What was the survival of the spacer free from unplanned reoperation or removal, the cumulative incidence of symptomatic infection, and the overall (Kaplan-Meier) survivorship of the patients? (2) What is the cumulative incidence of mechanical complications (spacer fracture or dislocation)? (3) What is the ambulatory status of patients who have retained their spacers? METHODS:Between March 2011 and July 2023, a total of 111 and 152 patients underwent first-stage revision with an articulating spacer placement as part of a planned two-stage procedure for chronic PJI after THA and TKA at our institution, respectively. Of these, 21% (23 of 111) in the THA group and 24% (37 of 152) in the TKA group did not undergo the anticipated second-stage reimplantation at our institution at least 1 year after spacer placement. Among the original cohorts, 2% (2 of 111) of patients who underwent THA and 3% (4 of 152) of patients who underwent TKA subsequently underwent second-stage reimplantation at outside institutions when reviewed, leaving 19% (21 of 111) in the THA group and 22% (33 of 152) in the TKA group with retained spacers. Of the original cohorts, 7% (8 of 111) in the THA group and 5% (8 of 152) in the TKA group did not have a 2-year follow-up, leaving 12% (13 of 111) of patients with THA and 16% (25 of 152) of patients with TKA available for analysis with a minimum of 2 years of follow-up or death in this retrospective study. The median (range) follow-up from spacer placement to the latest follow-up was 5 years (2 to 11) for patients with THA and 4 years (2 to 8) for patients with TKA. In the THA cohort, the median (range) age was 72 years (59 to 86), and eight patients were female; the median BMI was 32 kg/m2, and the median Charlson comorbidity index (CCI) was 3.5. In the TKA cohort, the median (range) age was 69 years (45 to 83), 13 patients were female, the median BMI was 31 kg/m2, and the median CCI was 4. Complication data following spacer placement were obtained from the electronic medical record and by telephone follow-up when needed. Clinical symptoms (swelling, erythema, warmth, fever, drainage, sinus tract, and pain), inflammatory markers (C-reactive protein and erythrocyte sedimentation rate), available radiographic findings, and laboratory test results (including synovial fluid analysis when obtained) were reviewed for evidence of infection or spacer-related mechanical failure. Infection after the spacer placement was defined as failure when the treating surgeon determined that an unplanned return to the operating room or spacer removal was warranted, acknowledging that postoperative evaluation thresholds varied among surgeons. Spacer-related mechanical failure was defined as spacer fracture or dislocation leading to reoperation or spacer removal. Patients were classified based on whether they underwent an unplanned reoperation or spacer removal. Patients who did not undergo unplanned reoperation or spacer removal were further categorized based on use of chronic suppressive antibiotics (decisions regarding chronic antibiotic therapy were made by the treating surgeon and/or infectious disease team). Patients who underwent reoperation were those who returned to the operating room because of concerning clinical, imaging, and/or laboratory findings of infection or mechanical complications, and the treating surgeon decided to proceed with revision surgery. All reoperation decisions were made by fellowship-trained arthroplasty surgeons with high-volume experience in two-stage revision. We used a competing-risks model to estimate survival of the spacer free from unplanned reoperation or removal attributable to infection or mechanical complications (calculated as 1 minus the corresponding cumulative incidence), with death treated as a competing event. Kaplan-Meier analysis was used to estimate patient survivorship, with death as the endpoint. Mortality data were obtained from medical records and hospital databases and were confirmed by telephone follow-up with family members and public records when needed. Ambulatory status before and after spacer placement was summarized descriptively and reported only for patients with both prespacer and postspacer data available (10 THAs and 25 TKAs); no formal hypothesis testing was performed for ambulatory or functional measures. RESULTS:At 2 years of follow-up, the survival of the spacer free from unplanned reoperation or removal was 89% (95% confidence interval [CI] 80% to 99%) for patients with THA and TKA combined, the cumulative incidence of infection was 5% (95% CI 0% to 12%), and the Kaplan-Meier survivorship of the patients was 92% (95% CI 84% to 100%). The cumulative incidence of mechanical complications (spacer fracture or dislocation) was 5% (95% CI 0% to 13%). In the THA cohort (10 patients), ambulatory status before the first stage included two patients using a wheelchair, two using a walker, one using crutches, two using a cane, and three walking without assistive devices. At latest follow-up, four patients used a wheelchair, two used a walker, two used a cane, and two walked without assistive devices. In the knee cohort (25 patients), ambulatory status before the first stage included two patients using a wheelchair, five using a walker, 13 using a cane, and five walking without assistive devices. At latest follow-up, two patients used a wheelchair, five used a walker, 13 used a cane, and five walked without assistive devices. CONCLUSION/CONCLUSIONS:Retained articulating spacers can provide infection control in selected patients who do not proceed to reimplantation after first-stage spacer placement for PJI. Although infection-free spacer survival is achievable, these patients remain at risk for mechanical complications, including dislocation and fracture, as well as progressive functional decline. These risks should be clearly discussed during preoperative counseling to align expectations and support informed decision-making. Further studies are needed to refine patient selection, improve spacer durability, and standardize definitions of treatment success in PJI. LEVEL OF EVIDENCE/METHODS:Level III, case series.

The multiply revised total knee arthroplasty (TKA) poses unique surgical challenges. Patients who present to the office with a failed TKA or revision TKA expect durable, long-term fixation and improved function, yet bone loss and extensor mechanism insufficiency can easily complicate the reconstruction. The aim of this American Association of Hip and Knee Surgeons symposium is to provide up-to-date guidance for re-revision TKA with a specific focus on 1) safe exposure; 2) improved fixation with impaction grafting; 3) improved fixation using porous metal structural augmentation; and 4) managing the patella. After reviewing this paper, the reader should feel comfortable with standard and extensile exposures of a revision knee arthroplasty, understand the technique and outcomes for impaction bone grafting and the use of porous metal augmentation, and develop an algorithm for treating and optimizing patellofemoral kinematics through augmentation and reconstruction techniques.

BACKGROUND:This study compares clinical and functional outcomes between simultaneous hardware removal during total knee arthroplasty (TKA) and staged TKA after prior hardware removal. METHODS:We retrospectively reviewed 155 patients who had prior knee hardware and underwent elective primary TKA between 2012 and 2024 at an urban academic institution. Patients were categorized into "simultaneous" removal during TKA (n = 127) or "staged" TKA after removal (n = 28), and stratified by hardware type (minor/moderate/major). RESULTS:Simultaneous procedures involved significantly less "major hardware," single incisions, and tibial stem extensions than staged procedures (32.3 versus 78.6%, P < 0.001; 81.9 versus 100%, P = 0.007; and 0.8 versus 10.7%, P = 0.019, respectively). Hardware, particularly the major type, was more often retained or partially retained in the simultaneous group (48.0 versus 21.4%, P = 0.008). Reoperation, revision, and infection rates did not significantly differ based on timing or hardware location. Simultaneous patients had smaller 3-month Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity and Interference score reductions (-1.6 versus -9.9, P = 0.006 and +0.4 versus - 7.2, P = 0.007, respectively), but greater 2-year Knee Injury and Osteoarthritis Outcome Score for Joint Replacement improvements (+25.0 versus - 1.1, P = 0.006) compared to staged patients. Simultaneous major hardware removal demonstrated significantly greater 2-year Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and PROMIS Pain Interference improvement (+32.0 versus -5.5, P = 0.001, and -6.2 versus +5.8, P = 0.027, respectively), but smaller 2-week PROMIS Pain Intensity score reduction (+2.2 versus -4.9, P = 0.050) compared to staged procedures. CONCLUSIONS:Simultaneous hardware removal during TKA led to higher retained major hardware rates and fewer single incisions than staged procedures, without increased reoperation or revision risks. Despite higher 3-month pain scores, simultaneous surgery achieved greater 2-year functional improvement, suggesting it offers advantages for select patients.

BACKGROUND:The Centers for Medicare and Medicaid Services now mandates the collection of patient-reported outcome measures (PROMs) before and after total knee arthroplasty (TKA), though their utility in predicting clinical outcomes remains unclear. This study compared the power of preoperative PROMs to predict clinical outcomes after TKA to established indices, including the Charlson Comorbidity Index and the Risk Assessment and Prediction Tool (RAPT). METHODS:We retrospectively reviewed 2,923 patients undergoing elective, primary, unilateral TKA who completed the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and four Patient-Reported Outcomes Measurement Information System (PROMIS) domains within 90 days preoperatively. Outcomes included same-day discharge (SDD) rate, prolonged length of stay (LOS ≥ 48 hours), nonhome discharge, 90-day readmission, and revision surgery. Predictive utility was assessed using receiver operating characteristic curves (area under the curve [AUC]) and multivariable logistic regressions. RESULTS:The RAPT was the strongest predictor of SDD (AUC = 0.697), extended LOS (AUC = 0.703), and nonhome discharge (AUC = 0.877). The PROMIS Physical Health (AUC = 0.609 for SDD; 0.607 for LOS; 0.696 for discharge) and PROMIS Mental Health (AUC = 0.613; 0.610; 0.655) demonstrated modest predictive value. In adjusted models, higher PROMIS Mental Health was associated with greater odds of SDD (odds ratio (OR) = 1.027, P = 0.003) and lower odds of extended LOS (OR = 0.975, P < 0.001). Higher PROMIS Physical Health was associated with decreased odds of nonhome discharge (OR = 0.935, P = 0.017). The Charlson Comorbidity Index was the strongest predictor of 90-day readmission (AUC = 0.604) and the only significant variable in adjusted models. There were no PROMs that were significant predictors of readmission or revision. CONCLUSIONS:Preoperative PROMs are associated with some clinical outcomes following TKA, but demonstrate limited predictive power compared to established tools like the RAPT score. These findings underscore the need for more robust, outcome-aligned PROMs to improve surgical planning in a value-based care model.

INTRODUCTION/BACKGROUND:Periprosthetic patellar fracture (PPPF) after total knee arthroplasty (TKA) is a rare complication, but can significantly affect patient function and implant survival. This study sought to better identify radiographic and anatomical risk factors for PPPF compared to a propensity-matched cohort. METHODS:We retrospectively queried 22,092 TKAs from January 2011 to December 2024 with patellar resurfacing at a single, urban, academic institution, yielding 44 (0.2%) verified cases of PPPF after TKA. Using propensity score matching on the basis of age, sex, body mass index (BMI), race, and Charlson Comorbidity Index, 44 control TKA patients who had patellar resurfacing without fracture were identified and analyzed using the same methods. RESULTS:The mean time to PPPF was two years after TKA (range, 10 days to 10 years), and 46% were atraumatic. A decreased native lateral patellar tilt (20.0 versus 22.6°, P = 0.039) and thinner native patellar thickness (22.6 versus 24.0 mm, P = 0.018) were associated with increased PPPF risk. Lateralization of the patella during resurfacing also increased risk (P = 0.011), as well as increased patellar component size (P = 0.034). On Receiver Operating Characteristic analysis, thinner native patella thickness was the most predictive of fracture risk (Area Under the Curve = 0.621); however, this result was underpowered, thus an optimal cutoff value could not be meaningfully established. CONCLUSION/CONCLUSIONS:The PPPFs are rare complications following TKA and may occur with or without trauma. Native patellar thickness was inversely correlated with fracture risk, and lateral positioning during resurfacing and increased component size were associated with increased risk. Patients who had PPPFs also demonstrated lesser lateral patellar tilt compared to non-fractured controls. Further investigation with a larger cohort may enable more precise risk factor stratification.